The spinal cord lies inside the vertebral column. It extends from the occipital bone of the skull to the level of the first or second lumbar vertebra. In adults, the spinal cord is 16 to 18 inches (42 to 45 centimeters) long and 0.5 inches (1.27 centimeters) in diameter. The spinal cord is the connecting link between the brain and the rest of the body. It is the site for integration of the spinal cord reflexes.